Author of the Book of Jeremiah

Author - Jeremiah (According to the Bible and Jewish Tradition). The book of Jeremiah is recognized as his own writings and a complete book just like the book of Isaiah. In Jeremiah 36:1-2, 4, 8, 32 it is written that Jeremiah collected his own writings and prophecies, some speculate that he put the book together with Baruch in the land of Egypt but there is no way to know for certain.

Link: https://bible-history.com/old-testament/bookofjeremiah